Video finderscopes

Which bit of sky is each telescope looking at?

Remote observing at the Global Jet Watch observatories works extremely well after local bedtime, but there are times when controlling one of these observatories from the other side of the planet is somewhat challenging. Thanks to a Fell Fund grant from the University of Oxford, our observatories are now equipped with "video finderscopes" which means we can see the wider field around where the telescope is pointing, in real time. We use integrating Watec cameras which are very light in weight and we have one of these riding on the top end of the telescope. This video finderscope is equipped with an 8mm lens to give us a relatively wide field (34x45 degrees) on the sky and is perfect for spotting clouds or other problems near where the telescope is pointing.

We have a second video finderscope (Orion 161mm focal length) further back on the optical tube assembly that gives us a much more zoomed-in, narrow field view (1.7x2.2 degrees) of exactly where the telescope is pointing. An example of this is shown in the adjacent image; the centre of the cross-hair is the exact point where the telescope is pointing and its black and white arms help us to identify this point irrespective of the sky background. This narrow-field finderscope is a great help in the acquisition of our spectroscopy targets, and in having a clear picture of what the telescope is seeing more generally. The data from these cameras are streamed into an Axis video encoder and we can access these directly over the internet at their own URL back in HQ in Oxford.